Fluids for Extreme Pressure and Wear Applications

ABSTRACT

Provided are compositions, additives for forming compositions, methods of operating apparatus in fluid communication with the compositions, and apparatus comprising the compositions. For example, the composition may include a polyalphaolefin component of from about 95% to about 99.5% w/w. The composition may include an additive component. The additive component may include an anti-wear agent. The anti-wear agent may be from about 0.1% to about 2% w/w. The anti-wear component may be characterized by an acid value of at least about 1 mg KOH/g. The additive component may include an aryl amine antioxidant agent, an anti-rust agent, and a metal deactivator agent. The composition may be characterized by a kinematic viscosity at 100° C. of at least about 5 centiStokes, a viscosity index of at least about 80, and an acid value in mg KOH/g of between about 0.1 and about 1.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. patent application Ser. No. 15/611,737, filed Apr. 25, 2016, which is a continuation-in-part application of U.S. patent application Ser. No. 15/137,799, filed Apr. 25, 2016, which is a continuation application of U.S. patent application Ser. No. 13/848,227, filed Mar. 21, 2013, now U.S. Pat. No. 9,321,980, which is a continuation application of U.S. patent application Ser. No. 12/924,984, filed Oct. 8, 2010. Each of the preceding applications is entirely incorporated herein by reference.

GOVERNMENT SUPPORT

This invention was made with government support under contract no. N00024-05-C-4169 awarded by the Department of Defense. The government may have certain rights in the invention.

FIELD OF THE INVENTION

Provided are lubricant and functional fluids suitable for high-stress applications.

BACKGROUND

Lubricants and functional fluids used in submarine propulsion systems may encounter challenging operating conditions in terms of pressure, wear, service life, and the like. Submarines may function independently such that their operating systems may need to perform reliably over long time periods. If a problem occurs with a submarine at sea, the chances for outside assistance may be remote. It is desirable that a lubricating fluid in a submarine be reliable, and, due to space and weight restraints, be multifunctional.

The current lubricating oil used in U.S. Navy submarines (known as 2190-TEP) is a mineral oil based fluid that meets the military specification MIL-PRF-17331. This oil has been used in submarines for the past forty years, but the U.S. Navy has increased the severity of the operating conditions in its fleet. For example, compared to past systems, the U.S. Navy now has faster new drive systems that have much higher gear-to-fluid volume interactions, operating under higher operating temperatures, which leads to more thermal efficiency. The net result of these more stressful operating conditions is that the existing 2190-TEP fluid is failing more quickly leading to high oil replacement and high disposal costs.

Problems observed in conjunction with these more stressful operating conditions include (a) high depletion of antioxidants in the mineral oil based 2190-TEP fluid, (b) sharp increases in total acid number and (c) severe off-gassing events. Degradation leads to the formation of components such as formaldehyde and carbon monoxide that can be particularly hazardous in the close operating conditions of the submarine.

The present application appreciates that providing fluid compositions, for example, to provide lubrication or other functions in high stress operating conditions, such as U.S. navy submarines, may be a challenging endeavor.

SUMMARY OF THE INVENTION

In one embodiment, a composition is provided. The composition may include a polyalphaolefin component in a percentage, w/w of the composition, of from about 95% to about 99.5%. The composition may include an additive component. The additive component may include an anti-wear agent. The anti-wear agent may be, in a percentage, w/w of the composition, of from about 0.1% to about 2%. The anti-wear component may be characterized by an acid value of at least about 1 mg KOH/g. The additive component may include an aryl amine antioxidant agent. The additive component may include an anti-rust agent. The additive component may include a metal deactivator agent. The composition may be characterized by a kinematic viscosity at 100° C. of at least about 5 centiStokes. The composition may be characterized by a viscosity index of at least about 80. The composition may be characterized by an acid value in mg KOH/g of between about 0.1 and about 1.

In another embodiment, an additive composition for a lubricant or functional fluid is provided. The additive composition may include an anti-wear agent in a percentage, w/w of the additive composition, of from about 10% to about 30%. The anti-wear component may be characterized by an acid value of at least about 1 mg KOH/g. The additive composition may include an aryl amine antioxidant agent, in a percentage, w/w of the additive composition, of from about 10% to about 30%. The additive composition may include an aryl amine antioxidant agent, in a percentage, w/w of the additive composition, of from about 10% to about 30%. The additive composition may include an alkyl or alkenyl succinic acid ester anti-rust agent. The additive composition may include a tolyl triazole derivative metal deactivator agent.

In one embodiment, a method of operating an apparatus using a composition is provided. The method may include placing a plurality of components of the apparatus in fluid communication with the composition. The composition may be a fluid. The composition may include a polyalphaolefin component in a percentage, w/w of the composition, of from about 95% to about 99.5%. The composition may include an additive component. The additive component may include an anti-wear agent. The anti-wear agent may be, in a percentage, w/w of the composition, of from about 0.1% to about 2%. The anti-wear component may be characterized by an acid value of at least about 1 mg KOH/g. The additive component may include an aryl amine antioxidant agent. The additive component may include an anti-rust agent. The additive component may include a metal deactivator agent. The composition may be characterized by a kinematic viscosity at 100° C. of at least about 5 centiStokes. The composition may be characterized by a viscosity index of at least about 80. The composition may be characterized by an acid value in mg KOH/g of between about 0.1 and about 1.

In another embodiment, an apparatus including a composition is provided. A plurality of components of the apparatus may be in fluid communication with the composition. The composition may be a fluid. The composition may include a polyalphaolefin component in a percentage, w/w of the composition, of from about 95% to about 99.5%. The composition may include an additive component. The additive component may include an anti-wear agent. The anti-wear agent may be, in a percentage, w/w of the composition, of from about 0.1% to about 2%. The anti-wear component may be characterized by an acid value of at least about 1 mg KOH/g. The additive component may include an aryl amine antioxidant agent. The additive component may include an anti-rust agent. The additive component may include a metal deactivator agent. The composition may be characterized by a kinematic viscosity at 100° C. of at least about 5 centiStokes. The composition may be characterized by a viscosity index of at least about 80. The composition may be characterized by an acid value in mg KOH/g of between about 0.1 and about 1.

BRIEF DESCRIPTION OF THE DRAWINGS

FIGS. 1A-1C include depictions of an apparatus used in a wear test used to validate results obtained in accordance with an example embodiment;

FIG. 1A is an illustration of a specimen configuration;

FIG. 1B is an illustration of a gear material;

FIG. 1C is an illustration of specimen processing;

FIG. 2 is a graph of the parameters of the results obtained in a high speed load capacity test, validating the beneficial characteristics obtained in accordance with an example embodiment;

FIG. 3 is a table that describes, in part, various example formulations of the composition;

FIG. 4 is a table that describes, in part, various example formulations of the composition;

FIG. 5 is a table that describes, in part, various example formulations of the composition; and

FIG. 6 is a table that describes, in part, various example formulations of the composition.

DETAILED DESCRIPTION

Various embodiments of the invention described herein may address the shortcomings of the prior art.

The more rigorous performance conditions demanded by newer ships may be handled by lubricating using the fluid composition of the present invention. In addition to submarines, newer surface ships with controllable pitch propeller systems have placed additional demands on the existing 2190-TEP lubricant. The improved properties of the present invention may also find advantageous use in place of existing hydraulic fluids, air compressor fluids and reducing gear fluids. Another advantage of the present invention is that a single formulation may be produced, stored and sourced for a variety of uses, which may be especially beneficial while at sea. Accordingly, applications for the present invention include lubricating and hydraulic oil, and other functional fluids for motion control, steam turbines and gears in ships and submarines, as submarine air compressor lubricating oil, and in controllable pitch propeller systems in ships and submarines. Of particular interest in many military applications are new lubricants or functional fluids that are able to provide both corrosion resistance and lubricating properties. Until now no synthetic lubricant composition has met certain stringent military requirements such as those in U.S. military specification MIL-PRF-17331 for both lubricating and anticorrosive properties.

In addition, lubricant or functional fluid additive packages and lubricants and functional fluids of the present invention may find additional commercial applications in lubricating environments involving desired low turnover and/or high gear-to-fluid volume interactions, such as may be found, for instance in wind turbine gear systems. Many of the issues faced in submarines are also presented in wind turbines, where it may be desirable to operate over long operating time intervals in remote locations, and with substantial effort and expense associated with lubricant change-over.

The invention includes, inter alia, an additive package, a lubricant or functional fluid including the additive package, apparatus containing the lubricant or functional fluid, and methods of operating apparatus using the lubricant or functional fluid.

In various embodiments, a composition is provided. The composition may include a polyalphaolefin component in a percentage, w/w of the composition, of from about 95% to about 99.5%. The composition may include an additive component. The additive component may include an anti-wear agent. The anti-wear agent may be, in a percentage, w/w of the composition, of from about 0.1% to about 2%. The anti-wear component may be characterized by an acid value of at least about 1 mg KOH/g. The additive component may include an aryl amine antioxidant agent. The additive component may include an anti-rust agent. The additive component may include a metal deactivator agent. The composition may be characterized by a kinematic viscosity at 100° C. of at least about 5 centiStokes. The composition may be characterized by a viscosity index of at least about 80. The composition may be characterized by an acid value in mg KOH/g of between about 0.1 and about 1.

In some embodiments, the polyalphaolefin component may be, in a percentage, w/w of the composition, of one of about 95, 95.5, 96, 96.5, 97, 97.5, 98, 98.5, 99, or 99.5, or a range between any two of the preceding values, for example, from about 95% to about 99.5%. The polyalphaolefin component may be any polyalphaolefin component, or a blend thereof, such as commercially available polyalphaolefin compositions and blends. Examples of commercially available polyalphaolefin compositions are typically sold according to nominal kinematic viscosity at 100° C. in centiStokes, e.g., SYNTON® PAO 40 (Chemtura Corporation, Middlebury, Conn.) has a kinematic viscosity at 100° C. of 40 centiStokes; SynBase Polyolefin 40 (Solitex, Inc., Houston, Tex.) has a kinematic viscosity at 100° C. of 41-43 centiStokes; SYNFLUID® PAO 40 (Chevron Phillips Chemical Company LP, The Woodlands, Tex.) has a kinematic viscosity at 100° C. of 39 centiStokes; and the like. In various embodiments of the composition, the polyalphaolefin component may include any such component or blend thereof with desired kinematic viscosity. For example, the kinematic viscosity of the composition at 100° C. in centiStokes may be about, or at least about, one or more of: 10, 10.25, 10.5, 10.75, 11, 11.25, 11.5, 11.75, 12, 12.25, 12.5, 12.75, 13, 13.5, 14, 14.5, 15, 17.5,20, 25, 30, 35, 40, 45, 50, 75, or 100, or a range between any two of the preceding values, for example, between about 10 and about 100. In various embodiments, the kinematic viscosity may be determined at least in part by the polyalphaolefin component. The desired kinematic viscosity of the fluid composition may be approximately selected by mixing various amounts of commercially available polyalphaolefin fractions. FIGS. 3-6 are tables that show various fluid compositions in which different amounts of PAO fractions at various kinematic viscosities at 100° C. may be combined to arrive at a fluid composition having a corresponding overall kinematic viscosity.

In some embodiments, the viscosity index of the fluid composition may be about, or at least about, one or more of 80, 85, 90, 94, 95, 100, 105, 110, 115, 120, 125, 130, 135, 137, 140, 150, 175, 200, 250, 300, 350, or 400, or a range between any two of the preceding values, for example, between about 80 and 400. The viscosity index may be determined according to that described for synthetic fluids in ASTM D4638 (American Society for Testing Materials, West Conshohocken, Pa.).

In several embodiments, the fluid composition may include the additive in a percentage, w/w of the composition, of one or more of about: 0.5, 1, 1.5, 2, 2.5, 3, 3.5, 4. 4.5, or 5, or a range between any two of the preceding values, for example, between about 0.5% and about 5%. The fluid composition may consist essentially of the polyalphaolefin component and the additive. The fluid composition may consist of the polyalphaolefin component and the additive.

In various embodiments, the anti-wear agent may be present, in a percentage, w/w of the composition, of one of about 0.1, 0.2, 0.3, 0.4, 0.5, 0.55, 0.6, 0.65, 0.7, 0.75, 0.8, 0.85, 0.9, 0.95, 1, 1.05, 1.1, 1.15, 1.2, 1.25, 1.5, 1.75, or 2, or a range between any two of the preceding values, for example, of from about 0.1% to about 2%,

In some embodiments, the anti-wear agent may include one or more of: an alkylated triarylphosphate, e.g., alkylated with one or more C₃-C₆ alkyl groups, such as isopropylated triaryl phosphate, tert-butylated triaryl phosphate, and the like; an alkyl phosphate, e.g., with a C₄-C₁₈ alkyl group, such as octyl phosphate, decyl phosphate, dodecyl phosphate, tetradecyl phosphate, hexadecyl phosphate, combinations thereof, and the like; a diarylether phosphate ester; a diarylether phosphate diester diphosphate; combinations thereof; and the like. For example, the anti-wear agent may include one or more of: a C₃-C₆ alkylated triarylphosphate, a C₄-C₁₈ alkyl phosphate, a diarylether phosphate ester and a diarylether phosphate diester diphosphate.

In several embodiments, esters in the anti-wear agent may be partly esterified, e.g., partly esterified dodecyl phosphate, such that the anti-wear agent may be characterized by an acid value, e.g., according to D974 (American Society for Testing Materials, West Conshohocken, PA). For example, the anti-wear agent may be characterized by an acid value in mg KOH/g of one of about 1, 2.5, 5, 7.5, 10, 11, 12, 13, 14, 15, 17.5, 20, 22.5, 25, 27.5, 30, 35, 40, 45, 50, 75, 100, 125, 150, 175, or 200, or a range between any two of the preceding values, for example, of from about 1 to about 200. The amount of the anti-wear agent in the composition may be selected in view of the acid value of the anti-wear agent to provide the acid value described for the composition herein. For example, the total acid value of the fluid composition in mg KOH/g may be about: 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7. 0.8, 0.9, or 1, or a range between any two of the preceding values, for example, between about 0.1 mg KOH/g and about 1 mg KOH/g.

In various embodiments, suitable anti-wear agents may be obtained or requested according to the above characteristics from commercial sources of anti-wear agents, for example, DURAD® 310M, a mixture of isopropylated triphenyl phosphate and partially esterified C₈-C₁₆ phosphates (reaction products of a mixture of C₈-C₁₆ alcohols with phosphorus oxide), having a nominal acid value of 13 mg KOH/g (CHEMPOINT®, Bellevue, Wash.); certain REOLUBE® series phosphate ester additives (Canoil Canada Ltd., Mississauga, Ontario CA); certain FRYQUEL® series phosphate ester additives (ICL Industrial Products, Gallipolis Ferry, W. Va.); certain ADDITIN® series phosphate ester additives (Rhein Chemie Holland line, LANXESS Corporation, Pittsburgh, Pa.; certain Lubrizol products (Lubrizol Corporation, Wickliffe, Ohio); and the like. Suitable anti-wear agents may include or be obtained as described elsewhere herein.

In some embodiments, suitable antioxidants may include aryl amine antioxidants, for example, phenyl alpha naphthyl amines (PAN) and alkylated phenyl alpha naphthyl amines (APAN), e.g., NAUGALUBE® series PAN/APAN antioxidants (CHEMPOINT®, Bellevue, Wash.). Suitable antioxidants may include or be obtained as described elsewhere herein. The anti-oxidant may be present, in a percentage, w/w of the composition, of one of about 0.1, 0.2, 0.3, 0.4, 0.5, 0.55, 0.6, 0.65, 0.7, 0.75, 0.8, 0.85, 0.9, 0.95, 1, 1.05, 1.1, 1.15, 1.2, 1.25, 1.5, 1.75, or 2, or a range between any two of the preceding values, for example, of from about 0.1% to about 2%,

In several embodiments, suitable anti-rust agents may include, in some embodiments, the anti-wear agent itself. Suitable anti-rust agents may include, in some embodiments, alkyl succinic acid esters, alkenyl succinic acid esters, and the like, e.g. derivatives such as ADDITIN® RC 4801, (Rhein Chemie Holland line, LANXESS Corporation, Pittsburgh, Pa. Suitable anti-rust agents may include or be obtained as described elsewhere herein. The anti-rust agent may be present, in a percentage, w/w of the composition, of one of about 0.025, 0.045, 0.05, 0.055, 0.075, 0.100, 0.125, or 0.150, or a range between any two of the preceding values, for example, of from about 0.025% to about 0.15%,

In various embodiments, suitable metal deactivator agents may include, for example, triazoles, e.g., tolyl triazole derivatives such as ADDITIN® RC 8239, (Rhein Chemie Holland line, LANXESS Corporation, Pittsburgh, Pa.). Suitable metal deactivator agents may include or be obtained as described elsewhere herein. The metal deactivator may be present, in a percentage, w/w of the composition, of one of about 0.025, 0.045, 0.05, 0.055, 0.075, 0.100, 0.125, or 0.150, or a range between any two of the preceding values, for example, of from about 0.025% to about 0.15%,

In some embodiments, the aryl amine antioxidant may include one or more of: a phenyl alpha naphthyl amine and an alkylated phenyl alpha naphthyl amine. The anti-rust agent may include an alkyl or alkenyl succinic acid ester. The metal deactivator agent may include a tolyl triazole derivative.

In various embodiments, the anti-wear agent and the aryl amine antioxidant may be present in the composition in independently selected amounts. The anti-rust agent and the aryl amine antioxidant agent may be present in substantially equal amounts. The anti-rust agent and the metal deactivator agent may be present in the composition in independently selected amounts. The anti-rust agent and the metal deactivator agent may be present in substantially equal amounts.

In several embodiments, the composition may be characterized by a kinematic viscosity at 100° C. in centiStokes of between about 10 and about 20; a viscosity index of between about 150 and about 250; and an acid value in mg KOH/g of between about 0.2 and about 0.6. See, for example, the various example formulations in FIG. 3. The composition may be characterized by a kinematic viscosity at 100° C. in centiStokes of between about 5 and about 8; a viscosity index of between about 100 and about 225; and an acid value in mg KOH/g of between about 0.2 and about 0.6. See, for example, the various example formulations in FIG. 4. The composition may be characterized by a kinematic viscosity at 100° C. in centiStokes of between about 8 and about 10; a viscosity index of between about 150 and about 250; and an acid value in mg KOH/g of between about 0.2 and about 0.6. See, for example, the various example formulations in FIG. 5. The composition may be characterized by a kinematic viscosity at 100° C. in centiStokes of between about 10 and about 13; a viscosity index of between about 150 and about 250; and an acid value in mg KOH/g of between about 0.2 and about 0.6. See, for example, the various example formulations in FIG. 6.

In some embodiments, the composition may be characterized upon testing under ASTM D4638 for 72 h at 175° C. by a decrease in acid value. The decrease in acid value may be, for example, a percentage of about one or more of 5, 10, 20, 30, 40, 45, 50, 55, 60, 70, or 80, or a range between any two of the preceding values, e.g., a decrease of between about 5% and about 80%. The composition may be characterized upon testing under ASTM D4638 for 72 h at 175° C. by an increase in kinematic viscosity, e.g., at 100° C. The increase in kinematic viscosity may be, for example, a percentage of about one or more of 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 20, or 30, or a range between any two of the preceding values, e.g., an increase of between about 1% and about 30%.

In various embodiments, the composition may be characterized by a Wedeven Associates Machine load stage failure test rating value (WAM value) of about the same or greater compared to a WAM value measured under the same test conditions for at least one of: 2190-TEP; a first test formulation of the composition in which the anti-wear agent is replaced by a low acid number anti-wear agent characterized by an acid value of less than 1 mg KOH/g; a second test formulation of the composition in which the anti-wear agent substantially comprises a methylated triarylphosphate; a third test formulation of the composition that substantially excludes a partly esterified phosphate ester; a fourth test formulation of the composition that substantially excludes the aryl amine antioxidant; and a fifth test formulation of the composition that substantially excludes an alkyl or alkenyl succinic acid ester.

In several embodiments, the composition may be characterized by a rotating bomb oxidation test value (RBOT value, ASTM D2272) of about the same or greater compared to a RBOT value measured under the same test conditions for at least one of: 2190-TEP; a first test formulation of the composition in which the anti-wear agent is replaced by a low acid number anti-wear agent characterized by an acid value of less than 1 mg KOH/g; a second test formulation of the composition in which the anti-wear agent substantially comprises a methylated triarylphosphate; a third test formulation of the composition that substantially excludes a partly esterified phosphate ester; a fourth test formulation of the composition that substantially excludes the aryl amine antioxidant; and a fifth test formulation of the composition that substantially excludes an alkyl or alkenyl succinic acid ester.

In various embodiments, an additive composition for a lubricant or functional fluid is provided. The additive composition may include any aspect of the additive component described herein. For example, the additive composition may include an anti-wear agent in a percentage, w/w of the additive composition, of from about 10% to about 30%. The anti-wear component may be characterized by an acid value of at least about 1 mg KOH/g. The additive composition may include an aryl amine antioxidant agent, in a percentage, w/w of the additive composition, of from about 10% to about 30%. The additive composition may include an aryl amine antioxidant agent, in a percentage, w/w of the additive composition, of from about 10% to about 30%. The additive composition may include an alkyl or alkenyl succinic acid ester anti-rust agent. The additive composition may include a tolyl triazole derivative metal deactivator agent.

In one embodiment, a method of operating an apparatus using a composition is provided. The method may include placing a plurality of components of the apparatus in fluid communication with the composition. The composition may be a fluid. The composition may include a polyalphaolefin component in a percentage, w/w of the composition, of from about 95% to about 99.5%. The composition may include an additive component. The additive component may include an anti-wear agent. The anti-wear agent may be, in a percentage, w/w of the composition, of from about 0.1% to about 2%. The anti-wear component may be characterized by an acid value of at least about 1 mg KOH/g. The additive component may include an aryl amine antioxidant agent. The additive component may include an anti-rust agent. The additive component may include a metal deactivator agent. The composition may be characterized by a kinematic viscosity at 100° C. of at least about 5 centiStokes. The composition may be characterized by a viscosity index of at least about 80. The composition may be characterized by an acid value in mg KOH/g of between about 0.1 and about 1.

In several embodiments, the method may include any aspect of the composition as described herein. For example, the method may include, upon operating the apparatus with the fluid composition, causing in the fluid composition one or more of: a decrease in acid value; and an increase in viscosity.

The plurality of components of the apparatus may include, for example, one or more of: a hydraulic line, a hydraulic reservoir, a piston, a gear surface, a bearing surface, a cam surface, a compressor, a blade, a rotatable shaft, a propeller pitch controller, and a turbine. The apparatus may be included, for example, by a submarine, a ship, or a windmill.

In another embodiment, an apparatus including a composition is provided. A plurality of components of the apparatus may be in fluid communication with the composition. The composition may be a fluid. The composition may include a polyalphaolefin component in a percentage, w/w of the composition, of from about 95% to about 99.5%. The composition may include an additive component. The additive component may include an anti-wear agent. The anti-wear agent may be, in a percentage, w/w of the composition, of from about 0.1% to about 2%. The anti-wear component may be characterized by an acid value of at least about 1 mg KOH/g. The additive component may include an aryl amine antioxidant agent. The additive component may include an anti-rust agent. The additive component may include a metal deactivator agent. The composition may be characterized by a kinematic viscosity at 100° C. of at least about 5 centiStokes. The composition may be characterized by a viscosity index of at least about 80. The composition may be characterized by an acid value in mg KOH/g of between about 0.1 and about 1. The plurality of components of the apparatus may include, for example, one or more of: a hydraulic line, a hydraulic reservoir, a piston, a gear surface, a bearing surface, a cam surface, a compressor, a blade, a rotatable shaft, a propeller pitch controller, and a turbine. The apparatus may be included, for example, by a submarine, a ship, or a windmill.

Lubricant or Functional Fluid Additive

In some embodiments, the lubricant or functional fluid additive of the invention may be described as a lubricant or functional fluid additive for a polyolefin oil blend, including a mixture of: (a) an anti-wear component consisting essentially of 95% isopropylated triarylphosphate, which has the following general chemical structure:

and 5% dodecyl phosphate, which has the following general chemical structure:

the dodecyl phosphate being only partially esterified, the anti-wear component present in the polyolefin oil blend in a range of from about 0.75 percent to about 2.00 percent by weight; (b) an antioxidant component selected from the group consisting of alkylated phenyl-alpha-naphthylamine (“APAN”), phenyl-alpha-naphthylamine (“PAN”) and mixtures thereof, and present in the polyolefin oil blend in a range of from about 0.75 percent to about 2.00 percent by weight; (c) an anti-rust component including an alkylated succinic acid ester anti-rust agent, and present in the polyolefin oil blend in a range of from about 0.025 percent to about 0.075 percent by weight; and (d) a metal deactivator component including a tolytriazole derivative, which has the following general chemical structure:

and present in the polyolefin oil blend in a range of from about 0.025 percent to about 0.075 percent by weight.

The antioxidant component may be present in the polyolefin oil blend in a range of from about 1.00 percent to about 2.00 percent by weight. The anti-wear component may be, may consist essentially of, or may consist of Durad 310M.

The anti-wear component may be present in the polyolefin oil blend in a range of from about 1.00 percent to about 2.00 percent by weight. The antioxidant component may be, may consist essentially of, or may consist of NAUGALUBE® APAN or PAN, which has the following general chemical structure:

In this same regard, it was found that, where the anti-wear component consists essentially of APAN and/or PAN, or consists of APAN and/or PAN, the most improved anti-oxidative performance was achieved.

The anti-rust component may be present in the polyolefin oil blend in a range of from about 0.045 percent to about 0.055 percent by weight. The anti-rust component may be, may consist essentially of, or may consist of LZ-859, which has the following general chemical structure:

The metal deactivator component may be present in the polyolefin oil blend in a range of from about 0.045 percent to about 0.055 percent by weight. The metal deactivator component may be, may consist essentially of, or may consist of Irgamet 39.

The lubricant additive for a polyolefin oil blend may include a mixture of: (a) an anti-wear component that may be, may consist essentially of, or may consist of 95% isopropylated triarylphosphate and 5% dodecyl phosphate, the dodecyl phosphate being only partially esterified, the anti-wear component present in the polyolefin oil blend in a range of from about 1.00 percent to about 2.00 percent by weight; (b) an antioxidant component selected from the group consisting of alkylated phenyl-alpha-naphthylamine, phenyl-alpha-naphthylamine and mixtures thereof, and present in the polyolefin oil blend in a range of from about 1.00 percent to about 2.00 percent by weight; (c) an anti-rust component including an alkylated succinic acid ester anti-rust agent, and present in the polyolefin oil blend in a range of from about 0.045 percent to about 0.055 percent by weight; and (d) a metal deactivator component including a tolytriazole derivative, and present in the polyolefin oil blend in a range of from about 0.045 percent to about 0.055 percent by weight.

Lubricant/Functional Fluid Composition

The lubricant/functional fluid composition of the present invention may be of a lubricating viscosity and may include: (a) a polyalphaolefin having a viscosity of about 10 centiStokes at 100° C. and present in the lubricant or functional fluid composition in a range of from about 84 percent to about 88 percent by weight; (b) a polyalphaolefin having a viscosity of about 40 centiStokes at 100° C. and present in the lubricant or functional fluid composition in a range of from about 11 percent to about 13 percent by weight; (c) an anti-wear component that may be, may consist essentially of, or may consist of 95% isopropylated triarylphosphate and 5% dodecyl phosphate, the dodecyl phosphate being only partially esterified, the anti-wear component present in the polyolefin oil blend in a range of from about 0.75 percent to about 2.00 percent by weight; (d) an antioxidant component selected from the group consisting of alkylated phenyl-alpha-naphthylamine, phenyl-alpha-naphthylamine and mixtures thereof, and present in the polyolefin oil blend in a range of from about 0.75 percent to about 2.00 percent by weight; (e) an anti-rust component including an alkylated succinic acid ester anti-rust agent, and present in the polyolefin oil blend in a range of from about 0.025 percent to about 0.075 percent by weight; and (0 a metal deactivator component including a tolytriazole derivative, and present in the polyolefin oil blend in a range of from about 0.025 percent to about 0.075 percent by weight.

The polyalphaolefin characterized by a viscosity of about 10 centiStokes at 100° C. may be present in the lubricant or functional fluid composition in an amount of about 86 percent by weight. The polyalphaolefin characterized by a viscosity of about 40 centiStokes at 100° C. may be present in the lubricant or functional fluid composition in an amount of about 12 percent by weight.

The various parameters of the additive package may be as set forth above.

The fluids of the present invention optionally may include one or more dyes, such as Unisol Liquid Red BHF, or Silicone Oil (polydimethlysiloxane), such as Dow Corning 200, which has the following general chemical structure:

The fluid composition may include:

PAO 10 85.8 PAO 40 12.0 Durad 310M 1.0 NAUGALUBE ® APAN 1.0 LZ-859 0.10 Irgamet 39 0.10 Unisol Liquid Red BHF 0.010 Dow Corning 200 0.002

The fluid of the present invention may find uses in any application requiring high performance, with the advantages of stable storage and use in environments that may have to accommodate low lubricant or functional fluid turnover. Examples may include marine and submarine use, as well as lubrication and functional fluid applications in wind turbines and the like.

EXAMPLES Example 1

The following technical reports describe the development of the antioxidant as well as a brief chronological summary of the 2190-S fluid development.

The research was designed to develop a synthetic alternative to Navy 2190-TEP. A series of synthetic basestocks and mixtures were evaluated, such as polyalphaolefins, alkylated naphthalenes, diesters, polyol esters and polyalkylene glycols, all containing a common commercially available additive package. Lubrizol 857 additive was used, which is recommended at a treat level of 1.4-3.0% in petroleum basestocks to meet the requirements of Navy's MIL-PRF-17331 specification. The research identified 3 candidate fluids that looked promising in most regards, with the exception of rust protection.

Further research focused on improving the rust protection of the candidate formulations. The Lubrizol 857 package was recommended for use at 1.4-3.0%, and was applied initially at a level of 1.5%. Increasing the concentration of the LZ 857 to 3.0-5.0% improved the rust protection, but it was found to be insoluble in the PAO basestock at concentrations above 2.0%. One of the major components of LZ-857 is tricresyl phosphate (TCP) antiwear (AW) additive. Solubility experiments showed that TCP has poor solubility in PAO.

It became apparent that there was still a need to improve the solubility of the antiwear additive in PAO. Chemtura of Middlebury, CT manufactures TCP under the trade name Durad 125. The Durad product line includes a number of other alkylated triarylphosphate esters with larger alkyl groups on the triarylphosphate. Durad 300 is an isopropylated triarylphosphate and Durad 620B is a t-butylated triaryphosphate. It was found that substituting the methyl groups on TCP with isopropyl or t-butyl groups greatly improved the PAO solubility of these AW additives.

It was further determined to examine other components of the additive package to see what other attributes of the finished fluid could be improved by reformulation of the additive. The second major component of the Lubrizol 857 additive package is the antioxidant (AO). Most of the AO development effort was conducted over a period of several months. It was during this period that PAN and APAN were identified as desirable AO performers and BC-1 as a desirable finished fluid formulation.

A foaming test indicated that the BC-1 formula benefited from an antifoam (AF) additive to meet the specification requirements, so a polydimethylsoloxane, Dow Corning 200, was added, with the new formula being called BC-1A. BC-1A remained a desirable candidate for two years until evaluated against the existing 2190-TEP fluid in an FZG gear lubrication test. Although BC-1A met the MIL-PRF-17331 specification gear test requirement, it did not perform as well as 2190-TEP.

It was determined to adjust the formulation again by modifying the Durad AW additive. Durad 310M is a mixture of 95% Durad 300 isopropylated triarylphosphate and 5% dodecyl phosphate. The dodecyl phosphate is only partially esterified, leaving some free acid phosphate present that is believed to be more reactive towards active sites on a steel gear surface. The free acid phosphate is believed to act as a trigger to initiate the formation of an iron phosphate lubricating film at the asperity contacts of the rubbing steel surfaces. A test method was needed to optimize the AW characteristics and gear lubrication properties of the formulation.

The U.S. Navy has used the Ryder Gear Test as a means of evaluating aviation gas turbine engine oils. While it has enjoyed a successful history, it also has some drawbacks as a test. A few years ago, the Navy funded Wedeven Associates to develop an alternative test to simulate the speeds, loads and sliding forces experienced by gear teeth. See FIG. 1. The Wedeven Associates Machine (WAM) utilizes a steel ball rotating on a rotating disc, each of which are driven independently, allowing for a range of motion from full rolling motion to full sliding motion. To demonstrate the invention, 7 - 8 different formulations were prepared with varying concentrations of Durad 620B and Durad 310M. The WAM test results showed a level of 1% Durad 310M provided the most cost effective means of achieving the same AW characteristics and gear lubrication properties as the existing 2190-TEP fluid. This formulation is referred to as BC-1A-5 and is the current 2190-S formula.

One effective embodiment of the fluid composition includes:

PAO 10 85.8 PAO 40 12.0 Durad 310M 1.0 NAUGALUBE ® APAN 1.0 LZ-859 0.10 Irgamet 39 0.10 Unisol Liquid Red BHF 0.010 Dow Corning 200 0.002

Example 2 Antioxidant Evaluation

The effectiveness of various antioxidants in the synthetic fluid was evaluated using differential scanning calorimetry (DSC) in accordance with the ASTM D6186 method to measure the oxidation induction time of the fluid formulations. Initially the formulations were tested under conditions of atmospheric pressure and 200° C. Later the test conditions were modified by decreasing the temperature to 180 and increasing pressure to 500 PSI. An iron catalyst was also added to promote oxidation.

In both sets of tests, formulation BC-7 containing phenylalphanaphthylamine (PAN) and BC-1 containing alkylated phenylalphanaphthylamine (APAN) proved to offer superior oxidation resistance.

TABLE 1 Antioxidant Comparison 2190- TEP BC-1 BC-3 BC-4 BC-5 BC-6 BC-7 PAO-10 (B) — 87.8 85.8 85.8 85.8 85.8 85.8 PAO-40 (C) — 10.0 12.0 12.0 12.0 12.0 12.0 Durad 620B — 1.0 1.0 1.0 1.0 1.0 1.0 LZ-859 — 0.1 0.1 0.1 0.1 0.1 0.1 Irgamet 39 — 0.1 0.1 0.1 0.1 0.1 0.1 Antioxidants NAUGALUBE ® — 1.0 — — — — — APAN Vanlube 81 — — 1.0 — — — — NAUGALUBE ® — — — 1.0 — — — 640 Naugalube 438L — — — — 1.0 — — NAUGALUBE ® — — — — — 1.0 — 531 Ciba L06 — — — — — — 1.0 Total — 100.0 100.0 100.0 100.0 100.0 100.0 DSC OIT @ 200 C., 22 106 14 9 11 20 78 min. PDSC OIT @ 15 93 32 40 24 7 115 180 C., min (With 50 ppm Fe Catalyst)

These results demonstrate the unanticipated results obtained with the the present invention with respect to the antioxidant performance, as compared to other formulations outside the scope of the present invention.

Example 3 Lubrication Evaluation

Rapid and fairly economical tribological test methods that may simulate the sliding friction and forces of gear teeth, such as those developed by Wedeven Associates, use a WAM ball-on-disk machine as shown in FIG. 1. Both the ball and disk are made of AISI 9310 steel typically used for gear applications, and are independently driven so their rotational speeds and contact load can be controlled. The test was actually developed with funding from NAVAIR in an effort to develop an alternative to their Ryder Gear Test Method that has been routinely used to evaluate aviation gearbox and gas turbine engine oils. The lubrication characteristics of the 2190-S fluid were optimized through subjecting a series of formulations for WAM Load Capacity testing.

Originally, samples of Navy 2190-TEP and the current 2190-S (labeled BC-1A) were tested, along with two additional formulations BC-1A-2 and BC-1A-3. The formulation designated 2190-S (BC-1A) contained 1% Durad 620B anti-wear additive. BC-1A-2 contained 2% of Durad 620B and BC-1A-3 contained 1.5% Durad 620B and 0.5% Durad 310M. Navy 2190-TEP exhibited a WAM Load Stage Failure of 24, while the BC-1A, BC-1A-2 and BC-1A-3 gave load stage failures of 14, 18 and 23 respectively.

Based on these results, it became clear that the Durad 310M was a much more effective load carrying additive than Durad 620B. In order to optimize the formulation for cost and performance, three more fluids were prepared. BC-1A-4 contained 0.5% each of 620B and 310M, BC-1A-5 contained 1.0% 310M alone, and BC-1A-6 contained 1.0% each of 620B and 310M. These fluids produced load stage failures of 23, 26 and 26 respectively. BC-1A-5 is considered to be the optimum formulation because it provides the highest load capacity at the lowest anti-wear additive treat level. Fluid formulations and corresponding WAM load stage failure loads are listed in Table 2.

Durad 620B and 310M are similar compounds with important differences. Both are alkylated triphenyl phosphates, but the alkyl groups on the 620B are butyl groups, while those on 310M are isopropyl groups. More importantly, the 310M contains 5% of an alkyl acid phosphate, which gives the 310M and acid value of 10-15 mg KOH/g versus an acid value of 0.1 maximum for 620B. The free acid phosphate has a strong affinity for metal surfaces and forms lubricious surface films more readily than the neutral acid phosphate.

TABLE 2 Effect of Antiwear Additive Package on WAM Load Capacity Fluid Components 2190-TEP BC-1A BC-1A-2 BC-1A-3 BC-1A-4 BC-1A-5 BC-1A-6 PAO 10 85.788 84.788 84.888 85.888 85.888 84.888 PAO 40 12.000 12.000 12.000 12.000 12.000 12.000 Durad 620B 1.000 2.000 1.500 0.500 1.000 Durad 310M 0.500 0.500 1.000 1.000 NAUGALUBE ® 1.000 1.000 1.000 1.000 1.000 1.000 APAN LZ 859 0.100 0.100 0.050 0.050 0.050 0.050 Irgamet 39 0.100 0.100 0.050 0.050 0.050 0.050 Unisol Red 0.010 0.010 0.010 0.010 0.010 0.010 DC-200 0.002 0.002 0.002 0.002 0.002 0.002 TOTAL 100.000 100.000 100.000 100.000 100.000 100.000 100.000 WAM Load 24 14 18 23 23 26 26 Stage Failure

FIG. 2 is a graph of the parameters of the results obtained in a high speed load capacity test, validating the beneficial characteristics obtained in accordance with one embodiment of the present invention.

These results further demonstrate the unanticipated results obtained with the present invention with respect to the further anti-wear package performance, in addition to the results obtained with respect to the antioxidant performance described above as compared to other formulations outside the scope of the present invention.

Example 4 The Fluid Composition Surprisingly Decreases in Acid Value and Increases in Viscosity Under Oxidation and Corrosion Stability Testing

One significant problem observed in conjunction with the more stressful operating conditions used in current U.S. Navy submarine applications is that the prior art mineral oil based 2190-TEP fluid displays a sharp increases in total acid number under operating condition stresses. The increased acidity of the 2190-TEP fluid increases wear on parts and decreases the hydrolytic and oxidative stability of the fluid. Thus, the sharp increase in acid number indicates a corresponding decrease in lubricant properties and fluid lifetime, followed by increased wear and corrosion damage to the components in contact with the fluid.

A series of samples of the fluid composition were submitted to an oxidation and corrosion stability test according to ASTM D4638 (American Society for Testing Materials, West Conshohocken, PA). For example, a sample of 2190-S was prepared meeting the constituent amounts described for BC-1A-5 in Table 2. The sample had an initial viscosity of 87.11 centiStokes at 40° C. per ASTM D445) and 12.34 centiStokes at 100° C. per ASTM D445) and an acid value of 0.41 mg KOH/g (per ASTM D664). The sample was exposed to oxidation and corrosion stability conditions according to ASTM D4638 for 72 h at 175° C. Surprisingly and unexpectedly, the acid value decreased by over 46%, to 0.22 mg KOH/g, while the viscosity increased by 5.5%, to 91.90 centiStokes (at 40° C.). The decrease in acid value and increase in viscosity under oxidation and corrosion stability testing is surprisingly and unexpectedly contrary to that observed for the prior art mineral oil based 2190-TEP fluid and low acid number fluids such as BC-lA in Table 2. Moreover, the decrease in acid value and increase in viscosity under oxidation and corrosion stability testing is indicative of surprisingly and unexpectedly higher fluid stability and better preservation of lubricant and other fluid properties, which corresponds to better performance and better component protection.

The instant invention is shown and described herein in what is considered to be the most practical and preferred embodiments. It is recognized, however, that departures may be made therefrom which are within the scope of the invention, and that obvious modifications will occur to one skilled in the art upon reading this disclosure. 

What is claimed is:
 1. A composition, comprising: a polyalphaolefin component in a percentage, w/w of the composition, of from about 95% to about 99.5%; and an additive component, comprising: an anti-wear agent in a percentage, w/w of the composition, of from about 0.1% to about 2%, the anti-wear component characterized by an acid value of at least about 1 mg KOH/g; an aryl amine antioxidant agent; an anti-rust agent; and a metal deactivator agent; the composition being characterized by: a kinematic viscosity at 100° C. of at least about 5 centiStokes; a viscosity index of at least about 80; and an acid value in mg KOH/g of between about 0.1 and about
 1. 2. The composition of claim 1, comprising the additive component, in a percentage, w/w of the composition, of from about 0.5% to about 5%.
 3. The composition of claim 1, the anti-wear agent comprising a partly esterified phosphate ester.
 4. The composition of claim 1, the anti-wear agent comprising one or more of: a C₃-C₆ alkylated triarylphosphate, a C₄-C₁₈ alkyl phosphate, a diarylether phosphate ester and a diarylether phosphate diester diphosphate.
 5. The composition of claim 1, comprising the aryl amine antioxidant in a percentage, w/w of the composition, of from about 0.1% to about 2%.
 6. The composition of claim 1, one or more of: the aryl amine antioxidant comprising one or more of: a phenyl alpha naphthyl amine and an alkylated phenyl alpha naphthyl amine; the anti-rust agent comprising an alkyl or alkenyl succinic acid ester; and the metal deactivator agent comprising a tolyl triazole derivative.
 7. The composition of claim 1, the anti-rust agent comprising an alkyl or alkenyl succinic acid ester, the anti-rust agent and the metal deactivator agent each being independently present in a percentage, w/w of the composition, of from about 0.025% to about 0.15%.
 8. The composition of claim 1, characterized by one of: (a) a kinematic viscosity at 100° C. in centiStokes of between about 10 and about 20; a viscosity index of between about 150 and about 250; and an acid value in mg KOH/g of between about 0.2 and about 0.6; (b) a kinematic viscosity at 100° C. in centiStokes of between about 5 and about 8; a viscosity index of between about 100 and about 225; and an acid value in mg KOH/g of between about 0.2 and about 0.6; (c) a kinematic viscosity at 100° C. in centiStokes of between about 8 and about 10; a viscosity index of between about 150 and about 250; and an acid value in mg KOH/g of between about 0.2 and about 0.6; and (d) a kinematic viscosity at 100° C. in centiStokes of between about 10 and about 13; a viscosity index of between about 150 and about 250; and an acid value in mg KOH/g of between about 0.2 and about 0.6.
 9. The composition of claim 1, the composition characterized upon testing under ASTM D4638 for 72 h at 175° C., by at least one of: a decrease in acid value; and an increase in viscosity.
 10. The composition of claim 1, characterized by a Wedeven Associates Machine load stage failure test rating value (WAM value) of about the same or greater compared to a WAM value measured under the same test conditions for at least one of: 2190-TEP; a first test formulation of the composition in which the anti-wear agent is replaced by a low acid number anti-wear agent characterized by an acid value of less than 1 mg KOH/g; a second test formulation of the composition in which the anti-wear agent substantially comprises a methylated triarylphosphate; a third test formulation of the composition that substantially excludes a partly esterified phosphate ester; a fourth test formulation of the composition that substantially excludes the aryl amine antioxidant; and a fifth test formulation of the composition that substantially excludes an alkyl or alkenyl succinic acid ester.
 11. The composition of claim 1, characterized by a rotating bomb oxidation test value (RBOT value) of about the same or greater compared to a RBOT value measured under the same test conditions for at least one of: 2190-TEP; a first test formulation of the composition in which the anti-wear agent is replaced by a low acid number anti-wear agent characterized by an acid value of less than 1 mg KOH/g; a second test formulation of the composition in which the anti-wear agent substantially comprises a methylated triarylphosphate; a third test formulation of the composition that substantially excludes a partly esterified phosphate ester; a fourth test formulation of the composition that substantially excludes the aryl amine antioxidant; and a fifth test formulation of the composition that substantially excludes an alkyl or alkenyl succinic acid ester.
 12. An additive composition for a lubricant or functional fluid, comprising: an anti-wear agent in a percentage, w/w of the additive composition, of from about 10% to about 30%, the anti-wear component characterized by an acid value of at least about 1 mg KOH/g; an aryl amine antioxidant agent, in a percentage, w/w of the additive composition, of from about 10% to about 30%; an aryl amine antioxidant agent, in a percentage, w/w of the additive composition, of from about 10% to about 30%; an alkyl or alkenyl succinic acid ester anti-rust agent; and a tolyl triazole derivative metal deactivator agent.
 13. The additive composition of claim 14, the anti-wear agent comprising a partly esterified phosphate ester.
 14. The additive composition of claim 14, the anti-wear agent comprising one or more of: a C₃-C₆ alkylated triarylphosphate, a C₄-C₁₈ alkyl phosphate, a diarylether phosphate ester and a diarylether phosphate diester diphosphate.
 15. The additive composition of claim 14, characterized by the anti-rust agent and the aryl amine antioxidant agent being present in substantially equal amounts.
 16. The additive composition of claim 14, characterized by the anti-wear agent and the metal deactivator agent being present in substantially equal amounts.
 17. The composition of claim 1, the aryl amine antioxidant comprising one or more of: a phenyl alpha naphthyl amine and an alkylated phenyl alpha naphthyl amine.
 18. A method of operating an apparatus using a fluid composition, comprising placing a plurality of components of the apparatus in fluid communication with the fluid composition, the fluid composition comprising: a polyalphaolefin component in a percentage, w/w of the composition, of from about 95% to about 99.5%; and an additive component, comprising: an anti-wear agent in a percentage, w/w of the composition, of from about 0.1% to about 2%, the anti-wear component characterized by an acid value of at least about 1 mg KOH/g; an aryl amine antioxidant agent; an anti-rust agent; and a metal deactivator agent; the composition being characterized by: a kinematic viscosity at 100° C. of at least about 5 centiStokes; a viscosity index of at least about 80; and an acid value in mg KOH/g of between about 0.1 and about
 1. 19. The method of claim 18, comprising upon operating the apparatus with the fluid composition, causing in the fluid composition one or more of: a decrease in acid value; and an increase in viscosity.
 20. The method of claim 18, the apparatus comprised by a submarine, a ship, or a windmill. 